OBJECTIVE: Obesity and chronic sleep deprivation have both become increasingly pervasive medical problems in recent years. The prevalence of adult obesity has doubled over the past 30 years and continues to increase. Similarly the prevalence of type 2 diabetes has dramatically risen. Both medical conditions have enormous economic and societal costs. In addition, industrial societies attach an economic value to maximizing the waking period to the longest tolerable limit by sleeping as little as possible. Average sleep time has decreased over the last century by 2 hours. Chronically sleeping less has been associated with increased weight, endocrine and metabolic health risks including glucose intolerance, cardiovascular disease, and mortality. The possibility that the current epidemic of obesity and metabolic health risks may be partially related to insufficient sleep is now being recognized. The objective of this proof-of-concept, controlled trial is to investigate the impact of increasing sleep time on body weight and metabolic parameters in chronically sleep-deprived, obese subjects. STUDY POPULATION: 18-50 year old, obese (BMI 30-55) men and premenopausal women, who usually sleep less than 6 hours, mainly recruited from the Baltimore-Washington metropolitan area. Sleep duration will be assessed by the use of sleep logs and actigraphy. Secondary causes of sleep deprivation such as insomnia, psychological (depression), and medical conditions associated with poor sleep quality (including obstructive sleep apnea) will be exclusionary criteria. DESIGN: This is a randomized, 12-month duration, comparison-controlled clinical trial of sleep extension (Intervention Group) or continuation of habitual short sleep schedule (Comparison Group). The proposed treatment is an educational and behavioral intervention aimed at increasing sleep in a non-pharmacological fashion. The main analysis of the study will be to determine if additional sleep will result in a significant difference in body weight at the end of 12 months between the Intervention Group and the Comparison Group. In addition, we would like to establish whether 12 months of additional sleep will result in: a) a decreased prevalence of metabolic syndrome; and b) improved insulin sensitivity, body composition, and lipid profile. At the end of the 12-month intervention study (Phase 1, Efficacy Study), all participants will be given information about the potential benefit of more sleep and encouraged to increase sleep time. Health teaching about proper nutrition and adequate exercise will also be provided at that time to the Comparison Group. All participants will be evaluated 6 months later to assess the effects of this intervention in a real-life situation (Phase 2, Effectiveness Study). OUTCOME PARAMETERS: body weight, average number of hours of sleep/night, fasting glucose and insulin, oral glucose tolerance test, insulin sensitivity, body composition, various metabolic parameters, food intake, energy expenditure, and quality of life measures. RECENT STUDY UPDATES: To facilitate subject enrollment, an extensive advertisement campaign has been conducted over the last 12 months using the WEB, fliers posted in the community, radio and newspaper advertisements. The first patient was randomized in January 2007; as of August 31 2011, 126 subjects have been randomized. Consistent with the epidemiology of sleep deprivation, approximately 70% of screened subjects are women and 2/3 belongs to minority groups. Most common reasons for exclusion were: excessive sleep time, insomnia, severe sleep apnea, untreated major depression, regular use of sleep medications, BMI greater than 55. Based on the available limited data, asleep extension of 30-45 min on average is achieved by subjects assigned to the Intervention Group, as recorded by actigraphy. In general the behavioral modifications have been effective in increasing sleep duration, especially when tailored to the specific life style of the subject. Recommending a limitation in caffeine intake, avoiding strenuous exercise in the two hours before sleep time and providing continued motivation and positive feed-back to each individual subject via monthly visits has been proven to be effective. Similarly, an involvement of the sleep partner and the family of the study participant has been helpful. Based on the available clinical observations, subjects assigned to this group report improved energy levels and mood which are often associated with increased levels of physical activity as self-reported and objectively assessed by activity monitors.